Effectiveness of an intervention program in reducing postoperative infections. Italian PRINOS Study Group

From 1987 to 1989, the National Health Institute carried out a before and after intervention study in order to evaluate the effectiveness of active surveillance and of modification of patient care practices in reducing the incidence of postoperative infections. The initial study population consisted of 20 general and thoracic surgical wards in 12 hospitals; 11 wards were not able to complete the study and were therefore excluded from the analysis. In December 1988, after a 13-month period in which baseline infection rates were assessed in 4,096 patients, written protocols regarding modification of patient care practices were defined and applied. Effectiveness of intervention was evaluated comparing infection rates measured in a 6-month period in 1989 on 1,638 operated patients with those of the previous period. In the overall population, a reduction of 19% of nosocomial infections was observed after the intervention. When individual infection sites were considered, pneumonia rates were statistically significantly reduced by 39%; for the other infection sites the observed differences were not significant. Effectiveness of intervention varied by subgroups of wards. In three of the studied wards, surgical wound infections were significantly reduced by 72%, whereas in the remaining wards the intervention seemed to have no positive impact on infection rates. Nevertheless, the intervention seemed to have been effective in increasing the awareness of infection problems in two other wards. Results of the study suggest that a consistent reduction of postoperative infections can be achieved in surgical wards where usual patient-care practices differ from standard of patient care policies. Nevertheless, the observed variation in effectiveness of intervention by individual wards suggests that differences in structural and behavioral characteristics can affect the compliance with recommended standards.